It has been customary to provide some means for locking swords, bayonets and knives within their sheaths to prevent accidental dislodgement of these implements. This is particularly true with respect to sharp blade instruments such as, for example,a hunting knife. The common retaining means for a hunting knife is a segmented strap with a snap fastener to secure the strap around the handle of the knife.
The presence of a retainer strap on a knife sheath can interfere with removal of the knife from the sheath and replacement of the knife in the sheath. This can be very disconcerting to, say, a hunter who likely is occupied with other tasks at the same time that he needs to extract the knife from or return it to its sheath.
W.A. Villwock in his U.S. Pat. No. 3,008,617, granted Nov. 14, 1961, for "ARTICLE ENCASEMENT DEVICES" discloses the idea of positioning permanent magnets in pockets of the walls of a knife sheath to hold the knife within the sheath. The principal disadvantage of the Villwock sheath is the requirement that magnet retention pockets be embossed or otherwise formed in the walls of the sheath. Further, because Villwock proposes the use of small magnets of the metallic variety he presents the dilemma of whether to use only a few magnets with the risk of insecurely retaining the knife or to use many magnets with their attendant cost.
There continues to be a need for a magnetic knife retention sheath which is easily and inexpensively constructed and which offers reliability and ease of use.